


Sleep Demon

by Pat_A_Cat



Category: Red Velvet (K-pop Band)
Genre: F/F
Language: English
Status: In-Progress
Published: 2020-07-09
Updated: 2020-07-21
Packaged: 2021-03-04 18:33:53
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 3,201
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25160929
Author URL: https://archiveofourown.org/users/Pat_A_Cat/pseuds/Pat_A_Cat
Summary: Yeri is Joy’s sleep paralysis demon, but instead of hovering over her all threatening like she just curls up on her chest like an oversized cat.
Relationships: Kim Yerim | Yeri/Park Sooyoung | Joy
Comments: 7
Kudos: 73





	1. Chapter 1

**Author's Note:**

> This was born from my 2 am thoughts and overconsumption of tiktok but uh enjoy! : )

Yeri is Joy’s sleep paralysis demon, but instead of hovering over her all threatening like she just curls up on her chest like an oversized cat. She hisses and swats at Joy’s hands if she tries to move her, her pointed tail flicking around agitatedly behind her. Undisturbed she’ll fall asleep on Joy’s chest and purr like a lawn mower.  
  
-  
  
Yeri doesn’t take her job as a sleep paralysis demon very seriously. She’s supposed to freeze Joy in place to instill a feeling of helplessness and scare the shit out of her. She doesn’t really care to though; she’d rather just slack off and use Joy as a human heating pad for a few hours. She prevents Joy from moving by laying on her and keeps her up for a while every night and for Yeri that’s good enough.  
  
-  
  
As a sleep paralysis demon Yeri has the power to cause hallucinations and render people immobile, but since she never had any plans to use them her powers are pretty weak and she doesn’t have much control over them.

Yeri has a lot of raw power and is extremely hard working when she puts her mind to something so with a little bit of guidance she’d be quite powerful; too bad all she wants to do is soak up Joy’s body heat.  
  
-  
  
Okay so let me set the scene...

Sooyoung is a a well known model, having entered the industry at 18 she has steadily gained notoriety over the years to get where she is now, splayed across magazine spreads. She’d also picked up a love for fashion and at 23 decided to pursue her dream of becoming a fashion designer; she moved into an apartment in the big city and started getting exposure and pitching her ideas to prominent companies that she has connections with. Attempting to break into a new part of the fashion industry led to a lot of sleepless nights and stress that just compounded when she started developing dry skin and bags under her eyes.

Yeri’s a young sleep paralysis demon, sent out into the human world for the first time to finally enact her demonic duty. Yeri -sensing that Sooyoung had the makings of a good victim- slinked into her room to settle on her chest...  
  
-  
  
After realizing, and coming to terms with, the fact that a fucking demon was going to break into her room every night to chill on top of her she tried persuading Yeri into laying in a different way. When asking politely and nagging insistently both failed she bodily wrestled Yeri into being the little spoon. Sharp hissing and flailing limbs didn’t deter her from forcing the demon into a tight embrace. It was the first time in a long while that Joy could actually breathe well.

Yeri would never admit to it but she found the new position to be surprisingly pleasant, having Joy’s arms wrapped around her was much warmer than just laying on top of her. After that night Yeri was much more open to trying new positions, though she never stopped resisting solely so Joy couldn’t say ‘I told you so’ or something along those lines (the smug smiles she always gave her were annoying enough), purposely going limp whenever Joy tried to move her just to make things harder for the human.

Their favorite position is when Yeri is the big spoon. Yeri’s insticts compel her to try to immobilize Joy even if she isn’t actively thinking about it. Joy likes the feeling of Yeri’s deep purring vibrating through her with how close the demon’s chest was pressed against her back. The lack of horns pressed against her face was also a plus, even thinking about the amount of times Yeri had head butted her in the chin with them made her jaw ache. Yeri likes to be the little spoon when she’s particularly cold and on those days Joy even let her warm up her cold feet on her legs.  
  
-  
  
Yeri has shadow traveling powers. She can travel anywhere as long as there are shadows to enter and exit through, but the darker they are the less taxing it is on her.

The first few days Yeri broke into Joy’s room she tried to keep her out by locking her door and window and barricading them. When that didn’t work she set up a video camera to see what was going on at night. When she checked the film the next night and saw Yeri materializing out of the darkness she immediately gave up on keeping Yeri out of her room and instead started looking for an exorcist.  
  
-  
  
The first time Joy woke up with Yeri still cuddled up to her was a surprising yet pleasant experience. Up to that point she’d always wake up in bed alone despite having a nightly visitor. She didn’t know that Yeri could even stay for that long and during the day too.

It was also the first time she’d been able to see Yeri clearly and in her opinion, moonlight didn’t do her the justice she deserved. She spent the time waiting for the demon to wake up looking over her in great detail; from the curls of her horns and the patterns on her skin, all the way down to the way the demon’s tail was wrapped in spirals down her leg, the tip slapping against her ankle whenever the demon twitched in her sleep. Also she was completely nude, but Joy tried not to linger on that particular detail for too long.

Pitch black eyes fluttered open just as Joy had worked up the nerve to touch her, her thumb hovering over where milky pale met dark obsidian. The tension left Joy’s body when Yeri leaned into her touch, nuzzling against her hand.

“Good morning Kitten”  
  
-  
  
As a sleep paralysis demon Yeri is accustomed to the dark. She’s used to living in chilled shadows and her body reflects that.

Yeri’s body temperature is lower than a human’s. That’s why Yeri’s so obsessed with clinging to Joy- well initially at least. She soon finds herself enjoying the feeling of Joy’s arms around her waist and takes comfort in her physical presence. On hot days Joy loved the feeling of Yeri’s cool body pressed against her when she was overheated and sweaty, but in the winter Joy had to fight the instinct to kick Yeri out of her bed whenever she tried to infiltrate her cacoon of warmth with her icy touch.

Yeri also has spectacular night vision; her eyesight is actually sharper in the dark than it is in the light. So while Joy could barely see Yeri in the light of the moon, Yeri could easily make out every feature of hers. After they got closer Yeri would escort Joy on her occasional night trips to the bathroom. Half asleep, Joy was prone to tripping over whatever crap she discarded onto the floor for the night and stubbing her toe against door frames. Hearing a pained cry from Joy when she was waiting on her bed for her return was enough to have her barreling into the hall to check on her.

After that incident Yeri always helped Joy navigate at night. It started simply enough; Yeri would only intervene when Joy was about to run into a wall or fall with a sharp tug of the wrist or by wrapping her tail around her torso securely; otherwise, she’d just let the human stumble around. But Joy’s directionless wobbling was cutting into her cuddle time -all she wanted was for them to be back in the warmth of her bed already- so she started leading Joy to the bathroom by holding her hand or wrapping her tail around her wrist and leading her along. Yeri’s actions backfired on her and their night adventures devolved into Yeri half dragging half carrying (on days where she’s feeling particularly nice Yeri’ll give her a piggyback ride) Joy to the bathroom as Joy became more and more dependent on the demon to get her there.  
  
-  
  
Yeri used to only show up at night and spend hours cuddled up with Joy so when she starts staying around throughout the day they go through a sort of adjustment period.

Yeri’s not used to being apart from Joy for any length of time so when Joy starts moving around her apartment to do things Yeri clings to her like a koala. Latching onto her back, front, legs, and even her head once (Joy was not happy when Yeri tried to perch herself on her shoulders, they promptly fell because Joy didn’t have the strength to support a whole being coiled around her head). After a lot of scolding and the utilization of the dreaded flashlight Joy had gotten Yeri to stop.

The demon eventually settled for wrapping her tail around Joy’s wrist; she’d coil it around her wrist and spiral down into the palm of her hand. Joy would often absentmindedly play with it, looping it around her fingers or rubbing and toying with the tip.

When Joy’s sitting she lets Yeri indulge in her cuddly habits and Yeri savors her time sitting on or draped across Joy’s lap. When Joy’s cooking at the stove Yeri likes to squeeze into the space in front of her and hug her while burying her face in her chest or rest her back against her and watch her cook (Joy really thought she’d escaped the head butting). When they’re walking together and Yeri wants more contact she’ll force her way under Joy’s arm so that it’s draped across her shoulders and wrap an arm around Joy’s waist.  
  
-  
  
As a sleep paralysis demon Yeri’s used to being in the dark so she’s extremely light sensitive. It doesn’t hurt her, but it can freak her out and at worst make her uncomfortable. Bright light makes her skin tingle, like bugs are crawling across it. She’s also susceptible to sunburn (they learned that the hard way). Her eyesight also takes a toll in the light. In the dark Yeri’s eyesight is incredibly sharp, comparable to an eagle’s even, but in the light she’s only able to see about as well as a normal human.

When Yeri starts spending more time with her during the day Joy starts keeping her apartment dimmer. She partially closes her blinds so that the sunlight filters in lightly and keeps her room as dark as possible. She knows that Yeri likes to curl up in her bed while she waits for her to come home (what she doesn’t know is that Yeri’s built a nest in the corner of her closet that she uses when she’s feeling particularly lonely).

Joy’s flashlight quickly becomes the bane of Yeri’s existence. When Joy’s still trying to teach Yeri what not to do (“No kitten get out of the dryer!”) she learns that flashlights work about as well as a spray bottle would on an actual cat. A couple seconds under the beam was enough to deter her from doing most things, but she’s always a little miffed after Joy uses it.  


**Notes for the Chapter:**

> I basically just copy-pasted this from my Tumblr so I'd say that the formatting on that is more reader-friendly than however I decide to organize this mess on here


	2. Chapter 2

Sooyoung woke up in a cold sweat, gasping harshly against the weight on her chest. Her fingers slowly released their tight grip on her sheets when her frantic eyes settled on the familiar figure curled up on her chest. In the sparse moonlight she could see the demon wrapped tightly around herself, her black tail was coiled around Sooyoung’s torso -further squeezing the air out of her- and her dark hair spilled across Sooyoung’s shoulders, tickling her skin when she moved. 

As annoyed as she was at being woken up every night feeling like she just ran a marathon she knew the sleeping monster was much more agreeable when treated gently. She didn’t want a repeat of the first time she’d woken up to a demon laying on her chest; she’d take the heavy weight on her chest over actually suffocating again any day.

“Kitty.” Sooyoung whispered, poking a pale shoulder softly, then harder when the demon just let out a grumbly growl. She let out a huff, grabbing the demon’s long pointy ear and giving it a short tug. That caught the demon’s attention; she whipped her head around, baring her teeth and hissing viciously at Sooyoung.

Illuminated solely by the moonlight, she looked every part the demon Sooyoung assumed her to be. Her dark hair fell past her shoulders, a little mussed from sleep. Large black rams horns protruded from her skull and curled around her head. Her eyes were completely black, framed by black splotches of skin that spread over her face and down her neck in intricate patterns. The ear that Sooyoung pulled twitched, mostly black until the base where the color melded into the milky paleness of her other skin tone. Her curled lip revealed her razor sharp teeth, each one tapered to a knife-like point.

Sooyoung just rolled her eyes. As dangerous as the demon looked she was about as harmless as a kitten; she’d nicknamed her as such for a reason. “Oh hush up,” Sooyoung pushed away the demon’s face with her hand, “I should be the one who’s mad, waking me up every night...” She pinched her nose, wiggling the demon’s face side to side. She pulled her hand back quickly when the demon lunged for her, giggling when sharp teeth snapped around air. 

The demon hissed indignantly, cupping her nose and rubbing it out. She sent Sooyoung a glare when the girl continued to laugh at her, curling back up and tucking her face into her arm. 

Sooyoung’s laughter trailed off as the demon continued to just lie on top of her, disgruntled grumbling escaping from the curtain of hair hiding her face. She knew she’d really annoyed the other girl when she saw the glimpses of movement in the dark; the demon’s tail was flicking back and forth in a way that she’d come to learn as annoyance.

“I’m sorry kitty. ” she reached out to pet the demon’s head, but the girl batted her hand away with a hiss, eyes popping out over her arm to glare at Sooyoung. Even in her agitated state she was careful not to harm the human, hand raised to deflect if she dared try something again, but claws curled safely towards her palm.

“I was just teasing you,” when the demon didn’t budge, instead a hiss rising from her throat, Sooyoung knew she’d have to bring out the big guns. “I’ll make it up to you,” she offered her hand, palm up, the demon staring at it in suspicion, “please?” She wiggled her fingers.

Sooyoung knew she was in the clear when the demon scrambled forward to place her chin on Sooyoung’s hand. A purr rumbed from her throat when Sooyoung’s scratching fingers travelled up her jaw to settle under her ear, causing it to twitch erratically.

When Sooyoung stopped the demon mewled pitifully, heatbutting Sooyoung’s chin. “Kitty!” The demon’s horns crowded around her face, pushing up roughly against her cheeks until she grabbed them and forcefully held the demon away from her.

The demon whined, trying to bury her head back under Sooyoung’s chin, but Sooyoung’s firm hold kept her in place. The demon promptly changed tactics, giving Sooyoung her best puppy dog eyes.

Sooyoung knew she was going soft for the girl when she found her pitch black pleading gaze cute, but she just couldn’t help but relent. “You’re a real brat you know that? You wake me up in the middle of the night just to pet you and all I get for my efforts are sore fingers and crushed lungs.” Sooyoung complained even as her hands slid down to massage the base of the demon’s horns where she knew the girl liked.

And maybe it wasn’t that bad -waking up in a cold sweat every night her heart pounding against her ribcage- if it meant that she got to have the cute demon curled up on top of her, her purring lulling her back to sleep.


	3. Chapter 3

**Summary for the Chapter:**

> Just some lil tidbits about Yeri that people have asked me about

Does yeri talk?

She does! But as a demon she speaks dimoori sheol, language of the damned. Joy physically can’t speak it and Yeri doesn’t understand human languages so they have a little bit of a language barrier. For the most part they make due with body language and an assortment of animalesque sounds from Yeri. Yeri’s native tongue really only slips when she’s feeling exceptionally strong emotions. The first time Joy heard her speak was when she was really excited; her words sounded like nails on chalkboard with an hissing undertone, but it was endearing nonetheless. 

Over time Yeri learns basic words like yes and no but she mostly understands Joy through tone and body language. Due to her nature as a sleep paralysis demon she’s able to interpret Joy’s emotions accurately and has learned to communicate her own in an easily understandable way, plus she’s just naturally expressive (her tail gives away everything). 

Does Yeri ever get looks because of her tail and horns?

Yeri utilizes her demonic powers of illusion when they’re out and about so she looks like any other human. Thing is she’s not very good at it so it takes a lot of concentration and the illusion tends to flicker out if she gets distracted. It’s pretty mentally taxing so she can’t use it for long periods of time; if they’re out for a long time they usually take breaks in bathrooms or dark secluded areas where Yeri can relax and recoup. 

When there’s some kind of event happening, like an anime convention or something of the sort where Yeri’s appearance won’t be questioned, Joy brings her out in her demon form. It’s always a treat when they can; Yeri’s more energetic without the constant mental strain and she’s infinitely curious of everything. 

People do like to ask for pictures with her though and while Yeri doesn’t mind (she usually wouldn’t let people close to her so easily but if Joy thinks it’s safe it must be) Joy’s learned to be careful about it; the flash freaks her out and Joy does not want a distressed demon on her hands while out in public. 

So if sleep paralysis demon Yeri is completely nude and Joy just lets her cling to her all the time 😭 poor Joy

Lol I actually forgot I headcannoned this

Joy quickly decides to have Yeri wear her clothes for the sake of her own sanity. Yeri doesn’t mind, they smell like Joy. When Joy starts bringing her out of the apartment they go on a shopping spree and Joy has a ball buying her new clothes, practically using her as a dress up doll at every store they go to. Yeri liked hearing Joy gush about how cute she is in every outfit she had her try on. 

Yeri’s opinion on clothes is pretty mixed; she likes the thick full bodied clothes because they’re soft and they keep her warm, but the skimpier ones allowed for more skin on skin contact. She doesn’t really have much of a preference though and is content to wear whatever Joy wants her to.

**Author's Note:**

> I basically just copy-pasted this from my Tumblr so I'd say that the formatting on that is more reader-friendly than however I decide to organize this mess on here


End file.
